Crushing mill



Patented dan.. 35B, l.

narran stares l Ltdl earner lerstes.

AUGUST FISCHER, OF VIENNA, AUSTRIA, ASSIG-NOR 'IO LOUIS FISCHER AND JACOB FISCHER, BOTH OIE' PHILADELPHIA, PENNSYLVANIA, AND MARY RUNZ, OF AS- TORIA, NEW YORK. v

CRUSHING MILL.

Application filed November 5, 1920. Serial No. v422,046.

T 0 all whomit may concern.' f

Be it known that I, AUGUST FISCHER, residing at Vienna, in the lState of Austria, have invented certain new and useful Improvements in Crushing Mills (for which I have iiled applications in Austria Feb. 27, 1919, Patent No. 82,992; @Zeche-Slovakia, May 5, 1919; Poland, June 12, 1920; Hungary, May 12, 1920); and I do hereby declare the vfollowing to be a full, clear, and exact description of the invention, suchy as will enable others skilled in the art to which it appertains to make and use the same. Crushing mills with vertical runners, in which the material falls into a rotating drum-shaped sieve provided with internal ledges or plates for liftingv the particlesof the crushed material 4which have not fallen through the sieve in order to deliver them to a device carrying them back rto the grinding path of the crushing mill Aare known. The device for carrying back the coarse par- Y t-icles'consists in the known constructions of an inclined pipe orf chute, thel upper end lof which extends into the interior of the drumshaped sieve and the lower end of which is placed over the grinding-path of the mill. Of course the angle of inclination of the outlet ofthe grinding-path as well as that of the return pipe or chute must atleast correspond to the natural gradient of the .treat1 ed material, if the operation of the crushing-mill is not to be interrupted. A

The necessity'of assuring the natural gradient of the material in the arrangement of these channels, Vpermits only of limited ranges in the breadth of the drum-sieve, if this sieve is to be fully utilized. Therefore until now it was not possible to proportion the sieve sufficiently large in diameter to allow of a perfect sieving of the material. In order to overcome this drawback, it has been proposed to increase the diameter of the drum-sieve in the direction away from the mill, the material thereby sliding automatically upon the sieve towards the mill.

This invention relates to a crushing mill of the character referred to, in which the coarse particles of the treated material are conveyed back from the drum-sieve to the grinding path of the mill by a conveying device arranged in the axis of the rotating drum-sieve. rlhis makes it possible to make the sieve of any desired breadth and the internal lifting plates of the sieve raise the particles of the crushed material which have not fallen through the sieve until they fall intoy the inletl of the conveying device. Where the conveying device is arranged axially of the drum sieve, it is possible to dispense with the inclined return-conduits hitherto necessary, so that the breadth of thel dimm-shaped sieve .can be proportioned only with regard to the desired function of` the sieve withoutrenderingy ineflicient the return conveyance. Y h

In a crushing mill constructed according to this invention, it is also `possible-contrary to the known constructions-to enlarge the diameter of the drumesieve in the direction away from the millA so that the materia-l falling from the grinding path of the mill into the interior of. the drum-sieve auto-- matically slides therein away from the mill and spreads in a very thin layer upon the sieve to any desired extent, because the material which has sieve, is conveyed under all circumstances to the inlet of the return conveying device by means of the lifting plates ofthe sieve. The device for conveying the material back preferably consists of a pipe havinginternal screw-threads or screw-shaped ledges and a. ring-shaped inlet-hopper, thisj pipe being connected to the drum-sieve to rotate not fallenr through the y therewith. Sucha construction is illustrated in the, accompanying drawings, vin which Fig. 1 is a vertical section and in Fig. 2 is a sideview o -f the drum-sieve.

Upon the table 1 is arranged the circular grinding path 2, against which move the two The material-coming from the grinding path 2 enters the ydownwardly inclined outlet pipe 10 and falls into the interior of the drumvsieve 12. This sieve has the form of a frustum of a hexagonal pyramid, as shown in Fig. 2, and is yrotated by the shaft 7 byv means of the conical toothed wheel 9 meshing with a conical toothed wheel 13 fast on one end of a sha-fl? le, and a sprocket chain 1T passing over a sprocket wheel 15, also fast on said shaft 14C, and a sprocket wheel 16 fast on the shaft 18 of the drum-sieve 12.

The drum-sieve 12 preferably diverges away from the crushing mill so that the crushed material falling from the outlet pipe 10 into the interior of the drum-sieve 12 may spread automatically upon the sieve by being shifted outwardly in consequence of the divergence of the sieve. rEhe small particles of the material fall lthrough the meshes of the sieve, while coarse particles which cannot pass the meshes of the sieve remain upon the outer portion of it. In the interior of Vthe sieve there are fixed radial lifting plates 19 which by the rotation of the sieve convey with them these coarse particles and lift them until they slide from the plates and fall into the ring-shaped hopper 20 of the conveying-pipe 21. This conveying-pipe 21 is arranged in the axis of the drum-sieve 12 and extends towards the crushing mill vover one end of the grinding-path 2. The pipe 21 is provided on its inner side with screwshaped ledges 22 which convey the material falling into the pipe towards the grindingpath 2. The pipe 21 rotates with the drumsieve. The material then falls unto the grinding-path and is treated again by the runners and is further pulverized so that a great portion of it, after being again fed through the outlet pipe 10 to the drum-sieve 12, now passes the meshes ofthe latter.

Should portions of the repeatedly treated material be still too coarse, they will again be carried by? means of the plates 19 to the conveying pipe 21 and so be delivered a third time to the crushing-mill and so on.

The ring-shaped hopper 2O is preferably provided with radial partitions 23 in order to secure a regular feeding of the material to the conveying pipe 21.

It is obviousthat the axially acting conveying device allows of any desired breadth of the sieve because the coarse particles of the material may be conveyed back also from great distances. Therefore considerable spreading of the material upon the sieve is possible and in consequence thereof a very perfect sieving will take place.

The construction of the crushing-mill, of the sieve, of the conveying device for repeatedly conveying back the material to be treated and of the driving means may be varied in diierent ways.

lVhat I claim as my invention is:

1. A crushing mill comprising a rotating drum-shaped sieve provided with internal lifting plates, means for feeding crushed material to the interior Of the drum-shaped sieve and a rotating pipe Aarranged axially of the drum-shaped sieve, said pipe being provided in its interior with screw-shaped ledges and at its outer end with a ring-shaped hopper for receiving the material falling from the lift-ing plates and for directing it into the interior of the said rotating pipe for conveyance back to the grinding-path of the crushing mill.

2. A crushing mill comprising a rotating drum-shaped sieve provided with internal lifting plates, means for feeding crushed material to the interior of the drum-shaped sieve and a rotating pipe arranged axially of the drum-shaped sieve, said pipe being provided in its interior with screw-shaped ledges and at its outer end with a ringshaped hopper having in its interior partitions for the purpose described.

3. A crushing mill comprising a rotating drum-shaped sieve `diverging vin the direct/ion away from the crushing mill and provided with internal lifting plates, means for feeding the crushed `material to the interior of the drum-shaped Sieve and a rotating pipe arranged axially of the drum-shaped sieve, said pipe bein-g provided in its interior with screw-'shaped ledges and at its onter end with -a ring-shaped hopper for receiving the material falling from the lifting plates and directing it into the interior of the said rotating pipe for conveyance back to the grinding path of the crushing mill.

4. A crushing mill comprising a rotating drmnshaped sieve diverging in the direction away from the crushing mill and provided with internal lifting plates, means for feeding the crushed material to the interior of the drum-shaped sieve and a` rotating pipe arranged axially of the drum-shaped sieve, said pipe being provided in its interior with screw-shaped ledges and at its outer end with a ring-shaped hopper having invits interior partitions for the purpose described.

In testimony whereof I aiiix my Signature in presence of two witnesses.

AUGUST FISCHER.

Witnesses: y

' SInGrRiED NEUTLEN, JOHANN LUX. 

